Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/385

 least find abundant proof how very enigmatical the question as to the relative position of strata frequently is; a question of the first importance in geological inquiries.

§ 46. On leaving Watchet, the red rock is for a short distance similar to what is found eastward, but veins of gypsum very soon begin to appear, and they gradually increase in quantity. The rock here is of a bright brick red colour, and very friable; and is traversed in every direction from the top to the bottom by pure white veins of gypsum. Vast blocks of it have fallen down, and are piled above each other and strewed along the shore; in those that are within reach of the dashing of the waves the gypsum is nearly washed out, giving them a very singular appearance. The rock is not distinctly stratified, but the thickest veins of gypsum are parallel to each other, and nearly horizontal: it contains as usual the grey patches and stripes. The principal veins of gypsum are of different thicknesses; in some places they nearly equal three feet, and the red rock between them is penetrated by smaller veins branching off in all directions; but besides these there are other veins which traverse the rest in every possible way. There are also detached masses of gypsum which are surrounded on all sides by the red rock.

There are different varieties of the gypsum; it is in general white, but it is in some places flesh coloured and bright red. There are thick masses of a very pure compact alabaster fit for many purposes in the arts, and there are several fibrous varieties. In some places it is mixed with siliceous sand and small pieces of quartz, and where these parts are washed by the sea, the gypsum is dissolved, and leaves the quartzose parts projecting and very often in beautiful forms. I did not find it in any case crystallized